Preparation of hexaalkoxydisilanes



I bility Patented Sept. 30, 1952 STATES v PATENT g w v 2,612,511 7 7 PREBARATION .OFHEXAALKOXXDiSILANEST Bernard A. Orkin, Philadelphia, Pa., assignorEtol Socony-Vacuum Oil Company, Incorporated; a; x corporation ofNew York N Drawing.

,lhis invention release-bro d y o synth ti lubricants-having a combination of. desirable properties, namely, high, visfiiosity indices, low pour, points, andg-oodstability, Itis more par ticularly concerned, with, compoundshaving the formula, (RO)3SiSi(OR)3, wherein; R is' an a1? iphatic, an alicyclic,v an ;aryl,, an aralkyl, or a heterocyclic radical, which have the aforementioned combination. of desirable properties, and with agnovel method for'their, preparation.

The preparation. ofrproduetsa having the formula, (RQ)3,SiSi(QR)s,+ and, more specifically, hexaalkoxydisilaneahas been. described by Dolgov and Volnov [J.,Gen. Chem. (USSR), 1, 330

(1931) see C. A. 26; 2168 (1932)]. These compounds were prepared by the reduction of the,

is as set forth hereinbefore, and having the. aforementioned"combination. of; properties can. be

preparechbyfi a method which is simple 1 and "ef ficient', It has nowiqbeen discovered that compoundsi LtheafQrmu-Ia (ROhSiSik'ORis, can beipnepared by;-reacting ..-a; hex-ahalodisilane with; 811121601101 or; a; phenol yin accordance .with thefollowingzeQuation:

c2) zssisizsar-seon moisisneoiatnxx" wherein X is-a; halogen & ,11d;RfiSIa'-$d ;find hereinbefore. 7

Accordingly, it is abroadobject of the present invention to provide new synthetic lubricants. Another object isnto: providaanovel method for producing'them which is simple and efficient. A

further object is to provide'synthetic lubricants having the formula, (RO)3SiSi (OR)3, wherein R-is asset forth hereinbefore, which have high viscosity indices, low pour points, and goodsta- Other objects and advantagespf the present invention will become obvious to those skilled-in the art from thefollowing detailed descriptioni -Broadly stated, the present invention providessynthetic lubricants: having- -high viscosity in-v ices, low-pour points, and good stabilitmwhichcomprise compounds having the formula,

Applicationjseptember 2;;1943,

Serial No. 50,669 8 Claims.. (01. 26 1-5143 w-hemR is nal he i i an ali y li ia a v ie ral v o a het e yc i -radi a hich t e total number of carbon atoms and heterocyclic atomsin each molecule variesbetweenabout 42 and about and a methodfor: producing, them, w c compris s, r a in a he ehalee si-le with an-alcohol-or a phenoL,

- T e c hol 1 on, phe reactants u ili abl pt elt es ntheticub an s o the r sen invention are the, monohydroxy aliphatic aloo- .hols, alicyclic alcohols, aromaticalcohols, and

heterocyclic alcohols, and, phenols. Non-limiting examples,v are heptanol-l zsethylhexanol ll o'otanolsl octanol 2, decanol-l, cyclopentanol, cyclohexanol, .2 l-methylcyclohexanol, 3- met hyl1-- cyclohexanol, phenol, Z-methylphenol, 3-m ethyls phenol, 4-methylphenol, benzyl alcohol, u-naph-.

in commercial quantities.

' The number of. carbon atoms, or ,heterocyclic atoms v present in, thealcoholor i phenol reactant islimited solelyv by the requirement, mentioned hereinbefore, th the umpi he num e o c boniatoms and heterocyclicatoms: in, each mole of productvmust be between aboutAZ-and about 60. a generally speaking inorder to, obtain rela- 'tively'pure,compoundshaving the, .same numlza er I of. atoms per, radical, the alcohol. or, phenoll -res,

actant should, contain at least, seven carbon atoms and heterocyclic atoms per molecule to achieve; the requiredminimum. sum of gamma product. ,Itimustbe understood;- however, that. is within the concept of the-present invention to use a mixture of different alcohols and/or phenols toprepare,thetsynthetic lubricant products, so long as the minimum number of atoms in the product is achieved. Such products will not be pure compounds, but, nevertheless, they will possess the aforementioned desired properties of a synthetic-lubricant! w l'b p a t' v th e killed-i t ei t th r r e ent nven om s; p licab e to i the preparation of jcompounds; having fewer mama carbon atoms-and heterocyclic atoms; For -example; hexaethoxydisi-lane, having 12, car, bon atoms per molecule, cambe prepared by the reaction between a hexahal edisilaneand ethanol, in accordance with the -process-ofthe present Such products havingfewerthan 42 atoms per molecule" will not be utilizablecal. factor.

as synthetic lubricants, as contemplated herein, but they will beuseful as solvents, plasticizers,

, etc. The preparation of these products is considered to be within the scope of the present invention.

The hexahalodisilane reactants utilizable herein are *ihexachlorodisilane, hexabromodisilane, hexaiododisilane, and hexafiuorodisilane. Of

these, hexachlorodisilane and hexabromodisilane are especially preferred.

As shown in the equation exemplifying the reaction contemplated herein, the alcohol or phenol reactant is reacted with the hexahalodisilane reactant in a proportion of about six moles of alcohol or phenol reactant for each mole of hexhalodisilane reactant. In practice, however, it is preferable to use an excess of about. I

one mole of the alcohol or phenol reactant, i. e.,

a total of about seven moles per mole of hexa-; j

halodisilane. For practical reasons, it is 'preferable to carry out the reaction in a non-polar hydrocarbon solvent. Especially preferred for this purpose are the aromatic hydrocarbon solvents, such as, for example, benzene, toluene, and

will] vary between about 5 per cent and about 50 per xylene. The amount of solvent to be used cent, based on the total weight of the reactants.

The temperature of the reaction is not'a criti- In general, the temperaturewillbe the reflux temperature of the solvent used, and preferably, it varies between about 80 C. and about 140 C. Thetime of the reaction will de pend on the temperature employed- In practice,

the reaction is complete after heating the reaction mixture, at the preferred temperature, for a period of time varying between about two hours and about six hours, after all reactants have been added.

The desired reaction product is isolated by dis tilling off, under reduced pressure, excess alcohol or phenol reactant, any unreacted hexahalodisilane, and the reactants, as set forth hereinbefore, may be used to prepare a wide varietyof products in accordance wtih this invention. r

EXAMPLE 1 Hera (heasozny) disilafie To 26.9 grams of hexachlorodisilane in 150 cubic centimeters of benzene were added 70,

. The reaction mixture was' grams of hexanol l. heated atreflux temperature (about 80 about four hours.

C.) for Volatile materials, solvent and unreacted reactants, were removed by top-' ping the crude reactionproduct at 250 C. under a pressure of four millimeters. The product, after filtration through filtering clay, Weighed 55 grams.

It was, a ing the properties setforth in Table I.

non-polar hydrocarbon solvent. The desired synthetic lubricant product is .re-

light yellow mobile liquid havapparent that the products EXANIPLE 2 H era (Z-ethylhescomy) disilace Into a solution of 26.9 grams of hexachlorodisilane in 250 cubic centimeters of benzene, were introduced 91 grams of Z-ethylhexanol-l. The reaction solution was refluxed (at ab'out C.) for about-3 hours and then topped at 250 C. under a pressure of four millimeters. The topped product was filtered through filtering clay. The productthus obtained was a slightly viscous oil weighing '70 grams. Analysis showed that this product contained 7.15 per cent silicon (calculated 6.99 per cent). Pertinent data for this product are set forth in Table I.

EXAMPLE 3 H cxa (octowy) disilane To 26.9 grams of hexachlorodisilane in 200 cubic centimeters of benzene were added dropwise 91 grams of octanol-l. The reaction was'carried out and the product isolated in the manner set forth in Example 2. The 74 grams of light" yellow oil thus obtained contained 6.96 per cent silicon (calculated 6.99 per cent). Pertinentdata appear in Table'I. f

TABLE I P Kinegaatic yiieosity, our entis 0 es Example r g it, g V V5533? -65 7.94 2.80 i 208 e5 17. 49 4. 99 19s 25 13.16 3. 93 218 From the data set forthin- Table I, it will be having the formula, (RO)3SiSi(OR)3, in which the total number of carbon atoms and heterocyclic atoms is at least 42, are excellent synthetic lubricants having high viscosity indices and lowpour points. The criticalness of the minimum total number of carbon and heterocyclic atoms is demonstrated by. the data for the product of Example I. This product has 36 carbon atoms per moleculeandits low viscosity renders the productunsuitable for purposes .of lubrication.

The stability-"of synthetic lubricantsof this type =is-illustrated bygthe datainTable II,-obtained by comparing a sample of the product of Example 2 with an SAE 10 motor oil 'in:a laboratory bench-scale oxidation test. Thefimotor 'oilused for. comparative purposes is anxoil obtained from a parafiinic crude and has a kinematic viscosity of 40.5 cs. at 100 F. and 5.99 cs. at 210 Fr a viscosity index of 100, a pour point of +5 F., and a neutralization number of 0.05.

TABLE II I Viscosity Lead Sample N. N) Increase, ube Loss,

Percent sludge Mg Example 2.. 1.4 36 None 2. 2 SAE 10 Oil 15.0 95.0 None 235.0

1 Neutralization Num ber=Mg. KOH required to neutralize 1 gram of oil sample. I j In the test from which the data set forth in Table II were obtained, a 50-milliliter sample of 7 test oil was placed in a test tube containing an, oxidation catalyst comprising 15.6 square inches of iron, 0.78 squareinchof copper, 0.87 square inch of aluminum, nd a lead piece havinga' surface area of 0.16 square inch. The tube was placed in a constant temperature bath at about 300 F. A gas delivery tube was inserted into the oil and dry air was passed through the oil at a rate of five liters per hour. After 40 hours, the tube was removed and examined for sludge. The sludging of the oil forms a criterion of the tendency of the lubricant to form insoluble substances, organic and inorganic. The lead piece, which had been carefully weighed prior to the test, was removed and carefully weighed. The loss in weight indicates the tendency oi the lubricant to attack lead-containing bearing surfaces. The viscosity increase reveals the tendency of the lubricant toward polymerization. The neutralization number is a measure of the susceptibility of the lubricant to oxidize to acidic substances. I

From the data set forth in Table II, it will be apparent that the synthetic lubricants of the present invention are superior to mineral lubricating oils. They are not susceptible to oxidation, there is little tendency toward polymerization, and, finally, there is Very little attack on lead bearing surfaces.

, In addition to their utility as synthetic lubricants, per se, the products of the present invention are, in general, completely soluble in mineral lubricating oils. Accordingly, they can be used as extenders for lubricants, or as additives to lubricating oils for the purpose of imparting desirable properties thereto.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations. may be resorted to without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. A process for the production of compounds having the formula, (R0) 3SiSi(OR) 3, wherein R is a radical selected from the group consisting of aliphatic, alicyclic, aryl, aralkyl, thienyl, pyridyl, furfuryl, and quinolyl radicals, which comprises reacting a hydroxy compound selected from the group consisting of monohydroxyphenols and monohydroxy alcohols, with a hexahalodisilane in an aromatic hydrocarbon solvent,v and at a temperature of between about 80 C. and about 140 C.; said hydroxy compound being used in amounts equivalent to an excess over six moles for each mole of hexahalodisilane.

2. A process for the production of hexa(2- ethylhexoxy)disilane, which comprises reacting Z-ethylhexanol-l, with a hexahalodisilane'in an aromatic hydrocarbon solvent, and at a temperture of between about C. and about C.; said Z-ethylhexanol-l being used in amounts equivalent to an excess over six moles for each mole of hexahalodisilane. V

3. A process for the production of hexa(2- ethylhexoxy)disilane, which comprises reacting 2-ethylhexanol-1 with hexachlorodisilane in benzene and at a temperature of between about 80 C. and about 140 C.; said 2-ethylhexanol-1 being used in amounts equivalent to, an excess over six moles for each mole of hexachlorodisilane.

4. A process for the production of hexaoctoxydisilane, which comprises reacting octanol-1 with a hexahalodisilane in an aromatic hydrocarbon solvent, and at a temperature of between about 80 C. and about 140 0.; said octanol-l being used in amounts equivalent to an excess over six moles for each mole of hexahalodisilane.

5. A process for the production of hexaoctoxydisilane, which comprises reacting octanol-l with hexachlorodisilane in benzene, and at a temperature of between about 80 C. and about 140 C.; said octanol-l being used in amounts equivalent to an excess over six moles for each mole of hexachlorodisilane.

6. A compound having the formula (R0) 3SiSi(OR) 3 wherein R. is a radical selected from the group consisting of aliphatic, alicyclic, aryl, aralkyl, thienyl, pyridyl, furfuryl, and quinolyl radicals, in which the total number of carbon atoms and heterocyclic atoms in each molecule varies between about 42 atoms and about 60 atoms.

7. Hexa(2-ethylhexoxy) disilane.

8. Hexa (octoxy) disilane.

BERNARD A. ORKIN.

REFERENCES CITED The following references are of record in the file of this patent:

Martin: J. Chem. Soc. (London), vol. 105, pp. 286072 (1914).

Dolgov et al.: J. Gen. Chem. (U. S. S. R.) 1, No. 2, 330-39 (1931).

Abrahamson et al.: J. Org. Chem., vol. 13, Mar. 1948, pp. 275-79. 

1. A PROCESS FOR THE PRODUCTION OF COMPOUNDS HAVING THE FORMULA, (RO)3SISI(OR)3, WHEREIN R IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC, ALICYCLIC, ARYL, ARALKYL, THIENYL, PYRIDYL, FURFURYL, AND QUINOLYL RADICALS, WHICH COMPRISES REACTING A HYDROXY COMPOUND SELECTED FROM THE GROUP CONSISTING OF MONOHYDROXYPHENOLS AND MONOHYDROXY ALCOHOLS, WITH A HEXAHALODISILANE IN AN AROMATIC HYDROCARBON SOLVENT, AND AT A TEMPERATURE OF BETWEEN ABOUT 80* C. AND ABOUT 140* C.; SAID HYDROXY COMPOUND BEING USED IN AMOUNTS EQUIVALENT TO AN EXCESS OVER SIX MOLES FOR EACH MOLE OF HEXAHALODISILANE. 